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Gates/Y2E2 Walkthrough

Gates/Y2E2 Walkthrough. In the Field: Energy Audits and LEED . Benjamin Welle, P.E., C.E.M., LEED AP PhD Student, CIFE CEE Department Stanford University. Relevant LEED Credits-New Construction and Existing Building. HVAC Fundamentals – Chillers and Boilers

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Gates/Y2E2 Walkthrough

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  1. Gates/Y2E2 Walkthrough In the Field: Energy Audits and LEED Benjamin Welle, P.E., C.E.M., LEED AP PhD Student, CIFE CEE Department Stanford University

  2. Relevant LEED Credits-New Construction and Existing Building

  3. HVAC Fundamentals – Chillers and Boilers NC-EAPr1, EAPr2, EACr1, EACr3, EACr5 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1 • Chillers make cold water and boilers make hot water. • The chiller is typically the most energy-intensive piece of equipment in the plant as well as the most wasteful. • Most control sequences are not optimized. • Huge saving potential! Chiller Refrigeration Cycle Boiler

  4. HVAC Fundamentals – Pumps NC-EAPr1, EAPr2, EACr1, EACr3, EACr5 EB- EAPr2, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1 • Pumps move the CHW and HW throughout the building (via pipes) by converting electrical energy to pressure energy. • Most pumps are constant speed. • Pump “Laws”- The power the pump consumes varies (theoretically) by a cubed relationship to the flow. Actually, it varies to the 2.7 power. Pump Curve Pump Curve vs. System Curve Centrifugal Pump Pump “Laws”

  5. HVAC Fundamentals – Fans NC-EAPr1, EAPr2, EACr1, EACr3, EACr5 EB- EAPr2, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1 • Fans move air throughout the building (via ducts) by converting electrical energy to pressure energy. • Most fans are constant speed or 2-speed. Flow is regulated by either inlet guide vanes, discharge dampers, or variable-frequency drives. The latter is the most efficient. • Fan “Laws”- The power the pump consumes varies (theoretically) by a cubed relationship to the airflow. Actually, it varies to the 2.7 power. Typical AHU Typical Centrifugal Fan Part-Load Fan Eff. Fan “Laws”

  6. HVAC Fundamentals – VAV Boxes, Diffusers and Cooling Towers NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr6.2, IEQCr7.1 EB- EAPr2, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQCr2, IEQCr6.2, IEQCr7.1, IEQCr7.2 • VAV boxes control the volume of air supplied to a space and perimeter VAV boxes frequently have reheat. • Diffuser performance is extremely important and is quite often designed poorly (dump, Coanda effect, short-circuiting) • Cooling towers reject the heat removed from the building and created by the chiller compressor. Most fans are constant speed or 2-speed. In most cases, the cooling tower should have a VSD.

  7. HVAC Fundamentals – Water-side Systems NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQCr7.1 EB- EAPr2, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQCr2, IEQCr6.2, IEQCr7.1, IEQCr7.2 Central plant water-side distribution systems vary widely. Below are two of the most common types of systems. Variable-secondary systems are the most common, and are the most reliable. However, they don’t maximize the energy performance at part load conditions. Variable-primary systems are the most efficient type of system. Primary-Secondary Variable-Primary

  8. HVAC Fundamentals- Air-Side Systems NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2, IEQCr6.2, IEQCr7.1 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr2, IEQCr3, IEQCr6.2, IEQCr7.1, IEQCr7.2 • The basic air-side distribution system is shown to the right, and is frequently referred to as the ASHRAE “H”. • The outside air dampers frequently have economizer controls, which allows for free cooling. • Many systems do not required return fans. • Fan energy is minimized by good duct design. ASHRAE “H”

  9. HVAC Fundamentals – Sensible and Latent Loads NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2, IEQCr6.2, IEQCr7.1 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr2, IEQCr6.2, IEQCr7.1, IEQCr7.2 Air Qsensible(Btu/hr) = 1.08 x CFM x ∆T Qlatent(Btu/hr) = 0.67 x CFM x ∆G Water Qsensible(Btu/hr) = 500 x GPM x ∆T Airflow Change in Temperature (°F) Grains of moisture (7000 Gr/lb of water) Water Flow

  10. HVAC Fundamentals – Psychrometrics NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2, IEQCr6.2, IEQCr7.1 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr2, IEQCr6.2, IEQCr7.1, IEQCr7.2 Air psychrometrics is the study of moist and humid air and the change in air conditions. A typical HVAC process is shown below.

  11. HVAC Measures NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2, IEQCr6.2, IEQCr7.1 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr6.2, IEQCr7.1, IEQCr7.2 • General HVAC Measures (Existing): • CHW/HW rest • Schedule modification/setback • Install VFDs • Change delta-Ts • Install BAS/EMS/DDC • Replace old motors • Install economizers • Reduce condenser water temperature • Insulate piping and ductwork • General HVAC Measures (New): • All above EEMs • High-efficiency chillers (with VFD) and condensing boilers • Minimize duct and pipe runs

  12. Gates HVAC System

  13. Y2E2 HVAC Narrative-Cooling • Much of Y2E2 is naturally ventilated. At night, the building will open certain windows and atrium louvers to expel the day’s heat and pre-cool itself. • Occupants in north and east perimeter spaces should open their windows manually before leaving for the evening and close their windows upon arrival the next day, using the ceiling fan for circulation. • Occupants in spaces along the south and west facades should also open their windows at night and close their windows in the mornings. These spaces have also been outfitted with active beams for additional cooling for use as needed. These are individually controlled by the thermostats on the wall. • Interior spaces are also cooled with active beams, controlled by the wall thermostat. • The basement labs are conventionally cooled and can controlled at the thermostats.

  14. Y2E2 HVAC Narrative-Heating • North and east perimeter spaces have baseboard radiators controlled by individual thermostats on the walls. • South and west perimeter spaces are heated by the active beams. Control is also provided at the wall thermostat • The basement labs are heated conventionally and can be controlled via the thermostats. • Spaces in the interior of Y2E2 rely on the rest of the building for heat and don’t currently have heat sources of their own outside of people and electronic equipment loads.

  15. Y2E2 Building Finish Narrative • The exposed concrete is the finished floor. Not only does it save tons of synthetic materials from being manufactured and transported, but it also contributes to the overall thermal comfort of the building. • Offices along the south side of Y2E2 are outfitted with sun shades. • Polycarbonate panels and walls have been installed in order to share daylight with the interior of the building.

  16. Y2E2 Lighting & Fan Narrative • Most of the lighting on the upper three floors of Y2E2 is controlled by motion detectors and photocells. • In private offices, the motion detectors are located at the wall switch. • Ceiling fans are also controlled by the wall-mounted motion detectors.

  17. Y2E2- HVAC Diagram

  18. Y2E2- Chilled Water Piping Diagram (AHU and FC)

  19. Y2E2- Chilled Water Piping Diagram (Beams)

  20. Y2E2- Ventilation Diagram

  21. Building Commissioning NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2, IEQCr6.2, IEQCr7.1 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr6.2, IEQCr7.1, IEQCr7.2 • Building commissioning is one of the highest value-added energy efficiency measures for existing buildings or new construction, if not the highest. • Even in newly designed buildings there remains a HUGE disconnect between the building design/construction and maintenance and operation. • Improper use of the building’s energy management system not only negates the benefits of an energy-efficient design, it can also cause energy consumption GREATER than a properly operating building with outdated pneumatic controls. Many O&M managers simply have no idea what their system is doing. • “If you can’t figure it out, just disconnect it” mentally pervasive throughout the building industry. • Additional Commissioning LEED credit is usually pursued (and rightfully so).

  22. Lighting- Background NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQCr6.1 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQCr6.1, IEQCr8 • T12s vs. T8s vs. T5s- T8s are typically best, T5s if there are high operating hours, though costs are decreasing. • Incandescent vs. compact fluorescent lighting (CFL)- Always better to replace incandescent bulbs with CFLs. Color, rendering, and socket compatibility not much of an issue anymore. Retail is the toughest sell. You can frequently buy them for 30-40% retail price. Payback is negligible (don’t forget the HVAC savings!). • LEDs- You see these in exit signs, stoplights, and many display signs. This technology is rapidly developing and may soon replace many fluorescent applications. • Lighting controls- Occupancy sensors, dimmable ballasts, and photosensors are widely applicable. Very short payback. • This is the low-hanging fruit.

  23. Lighting- Measures NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQCr6.1 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQCr6.1, IEQCr8 • General Measures (Existing): • Replace T12s with T8s or T5s • Replace Inc. with CFLs • Install LED exit signs • Install occupancy sensors • Install photosensors and dimmable ballasts for perimeter zones • De-lamp and install specular reflectors • Install photocells or timeclocks on outdoor lighting • General Measures (New): • All above EEMs • Optimize lighting design/indirect lighting • Optimize natural daylighting Along with building commissioning, lighting retrofits hold the greatest energy efficiency potential for existing buildings worldwide.

  24. Envelope- Windows NC-EAPr1, EAPr2, EACr1, IEQCr6.1, IEACr7.1, IEQCr8 EB- EAPr1, EAPr2, EACr1, EACr3.2, IEQCr6.2, IEQCr7.1, IEQCr8 • Windows are the most problematic envelope component of existing buildings. • Many people are quick to say “install low-e double-pane windows” as a retrofit, but it rarely pays back. Window film is a much more viable option (south facing facades). In extreme weather locations, window replacement may be justified. • For new buildings, spectrally selective coatings, low-e being one type, are very desirable. It allow sunlight to pass through while minimizing IR heat gain. Coated glass typically better than tinted glass. • Avoid aluminum frames or ensure exceptional thermal breaks. • How much difference can a window film make on an existing building?

  25. Envelope- Measures NC-EAPr1, EAPr2, EACr1, IEQPr1, IEQCr7.1, IEQCr8 EB- EAPr1, EAPr2, EACr1, EACr3.2, IEQCr6.2, IEQCr7.1, IEQCr8 • General Measures (Existing): • Add insulation • Install efficient windows (double-pane, low-e) • Install window film • General Measures (New): • All above EEMs • Optimize site orientation, window placement (daylighting) • Optimize building footprint • Super-insulate (downsize or eliminate HVAC system) • Install air/vapor barriers • Minimize thermal breaks • Design for natural ventilation (pure or hybrid)

  26. Energy Code Impact on LEED Credits NC-EAPr1, EAPr2, EACr1, EACr3, IEQPr1, IEQCr7.1, IEQCr8 EB- EAPr1, EAPr2, EACr1, IEQPr1, IEQCr2, IEQCr7.1, IEQCr8 • Title 24 aggregates gas and electricity use (Btu/ft2). ASHRAE 90.1-1999 used the Energy Cost Budget method ($/ft2). LEED takes into account the relative cost of fuels, which means the most desirable credits vary by region, based upon the relative gas and electricity prices. • LEED 2.2 is based on ASHRAE 90.1-2004, which did not regulate process and receptacle loads. Title 24-2005 is no longer considered more stringent than 90.1-2004, so the requirements are the same. 90.1-2004 uses a Performance Rating Method (PRM), which again uses $$$$ as the benchmark. It includes process and receptacle loads, elevators, site lighting and non-conditioned lighting. • 25% of baseline is plug load, and is fixed, making it more difficult to achieve LEED points, though there are work-arounds. • Any good engineer will always used the performance-based compliance method, not the prescriptive.

  27. Thermal Comfort NC-EAPr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2, IEQCr6.2, IEQCr7.1, IEQCr7.2 EB- EAPr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr4, IEQCr6.2, IEQCr7.1, IEQCr7.2 Thermal comfort is physiological and psychological (subjective). A well-designed building is only acceptable to 80% of the occupants (by definition). ASHRAE 55 governs thermal comfort. Major Variables Influencing Thermal Comfort: 1. Air temperature 2. Activity level 3. Humidity 4. Clothing 5. Air Velocity 6. Mean radiant temperature Comfort Zone • Thermal comfort is a major problem in buildings built prior to 1995. Can you guess why?

  28. Daylighting NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr6.1, IEQCr8 EB- EAPr1, EAPr2, EQCr1, EACr3.3, EACr5.1, IEQCr4, IEQCr6.1, IEQ8 • “Daylight and Views” credits difficult to achieve. • Synergy between footprint reduction and D&V credits. Tradeoff with construction costs, zoning requirements, and thermal performance of the building. • Several spectrally selective coatings reduce visible sunlight significantly. • Difficult to incorporate into existing buildings. What’s there is what’s there typically. Controls can be installed to optimize lighting.

  29. Indoor Air Quality- Energy Conservation and IAQ NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr4, IEQCr9 • Discomfort is one of the key risk factors for indoor air quality complaints. • The cost of comfort control for the average building (i.e. heating, cooling and ventilating) is $2-$5/square foot/year. • The cost of labor for the average building is $200-$300/square foot/year. • It is not uncommon that comfort is sacrificed for energy conservation- but this may not make very good economic sense.

  30. Indoor Air Quality- Common Features in IAQ Complaint Buildings NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2 EB- EAPr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr4 • New building or recently remodeled (6 months of off-gassing) • Evidence of water intrusion or reports of water/excessive moisture in occupied spaces • Significant outdoor pollutants entrained into the occupied spaces • Limited (or no) outdoor air supplied to the occupied spaces • Reports of re-occurring discomfort complaints

  31. Indoor Air Quality- Potential Risks to Building Occupants and Building Owners NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2 EB- EAPr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr4, IEQCr9 • To employers: • Health and comfort complaints leading to concern about building safety, as well as disharmony and distrust • Increased absenteeism • Loss of productivity • Worker compensation claims • Investigating and resolving the complaints • To building owners: • The process of responding to and resolving the complaints • Disharmony with the tenant, and possible loss of tenant • The possible stigma of a “sick” building • Stress on building management and facilities personnel • Potential for tort liability claims and lawsuits

  32. Indoor Air Quality- Categories of Indoor Health Complaints NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2 EB- EAPr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr4, IEQCr9 • Common health complaints reported by building occupants: • - Sick Building Syndrome (SBS) • - Building Related Illnesses (BRI) • Reports of indoor air contaminants (e.g. odors, chemicals, dust on surfaces, appearance of mold stains) • Reports of uncomfortable conditions, such as uncomfortable temperatures, drafts, stuffy conditions, bad odors, high or low humidity

  33. Indoor Air Quality- Sick Building Syndrome NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2 EB- EAPr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr4, IEQCr9 • Symptoms: • Characterized as a cluster of common complaints. • Common features include symptoms only experienced after some period of time in the building, typically daily, on some days worse than others. • General complaints are headache, fatigue, and sleepiness. • Mucus membrane complaints are for the eye, nose, throat irritation, nasal blockage, congestion, sinus complaints, hoarse voice, skin discomfort, and breathing difficulties. • Symptoms are usually subjective, with no or limited clinical signs. • Not an uncommon type of complaint pattern, with some speculation that perhaps 50% of all buildings will be reported with such occupant complaints during their lifetime. • Causes (speculated): • Volatile Organic Compounds (VOCs), e.g. solvent vapors, from building materials, furnishings and fixtures off-gassing these chemicals. • Inadequate outdoor air supply, which allow pollutants to accumulate. • Microorganisms such as fungal spores • Perception or belief that there is something wrong with the building. • Common characteristics of SBS buildings: • More common in new or recently remodeled buildings (within the last five years). • Energy efficient designs, with restricted OA and no operable windows. • Comfort complaints usually accompany health complaints. • Women report health and discomfort complaints at twice the rate that men report. This is observed when other factors are controlled (salary, prevalence of women/men in the space, position within the organization).

  34. Indoor Air Quality- Building Related Illnesses NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2 EB- EAPr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr4, IEQCr9 • These are diagnosable illnesses usually with identifiable environmental causes. Some are serious public health issues. • Examples include Legionnaires disease, hypersensitivity pneumonitis, and allergic rhinitis. • The causes are the presence of biological agents frequently associated with improper treatment systems, water intrusion and infiltration. • True BRIs are rare as compared to SBS complaints.

  35. Thermal Comfort/IAQ Measures NC-EAPr1, EAPr2, EACr1, EACr3, EACr5, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr4, IEQCr6.2, IEQCr7.1, IEQCr7.2, IEQCr8 EB- EAPr1, EAPr2, EACr1, EACr3.2, EACr3.3, EACr5.1, IEQPr1, IEQCr1, IEQCr2, IEQCr3, IEQCr4, IEQCr6.2, IEQCr7, IEQCr8, IEQCr9 • General Measures (Existing): • Enhanced maintenance program • Increase OA • Install Demand Controlled Ventilation (DCV) • Clean ducts (or replace) • Provide local thermal and lighting controls • Adjust air velocity and RH • Install DDC EMS • Re-zone the space • General Measures (New): • All above EEMs • Design for natural ventilation (careful with this one) • Use low-emitting materials • Good construction IAQ management plan

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